Post
by Diana » Sat Sep 19, 2009 7:18 pm
If the 'Cotton rot' is smooth, grey or white patch it is likely a bacterial infection caused by Flavobacteria columnaris. Most fish antibiotics will help (it is a Gram negative bacteria). You could isolate this fish in a quarantine tank for treatment. It is cheaper to medicate a smaller tank, and the other fish may not have an active infection of this.
It is more common in warm water (over 76*F) and in water with high nitrates. Keep up the water changes.
If the patch looks like sort of a cottony-fuzzy growth then it is more likely a fungus infection. Most aquatic fungi will attack tissues that are already injured. Isolate the fish and treat, but I am not sure with what. You can clean off the area ONCE with Betadine. This can kill the healing tissues, though, so do not repeat the treatment unless the fungus gets worse. Best to keep the water as absolutely clean as possible. Lowest possible nitrates, lowest possible organic waste. If the fish is moved to a hospital tank keep the bottom of the tank bare and remove fish waste and fallen food promptly.
38 tanks, 2 ponds over 4000 liters of water to keep clean and fresh.
Happy fish keeping!